Mobile computing devices such as smart phones, tablet personal computers or ultra-mobile personal computers continue to evolve into computing devices that include more power intensive electrical components. These more power-intensive electrical components such as multi-core processors, graphics processors or system-on-a-chip combinations may not only be power intensive but may generate significant amounts of thermal energy during operation. In particular, microprocessors and the supporting electronic components in desktop and mobile computing devices may generate waste heat that can limit and/or impair the performance of the microprocessors and electronics.
The problem of excess heat generation during operation of electronic components may be exacerbated by recently implemented technology that may act to increase heat generation from a device or set of devices occasionally or sporadically. For example, to enhance the customer computing experience technologies have recently been deployed to vary the operating frequency of an electronic processor such as a central processing unit (CPU) to enable high performance computing when required. The short “bursts” of the operating frequency may give a user the impression of a very high-performance computing system while maintaining operation of the electronic components and overall computing system within designed thermal limits. These bursts of frequency can result in the computer exhibiting a responsiveness in performance to the user that may be referred to as “snappiness.” Although it may be desirable to further increase the frequency burst duration and/or operating frequency in such short bursts of performance, the large currents generated by the processor and components supporting the processor, such as onboard power supplies, may overheat, which may affect either the individual processor components, supporting connecting board material, and/or the Voltage regulator [VR], among other components.
One manner of accommodating this operation is to provide oversized components to support the short bursts of high processor frequency in order to help dissipate the concomitant large thermal transients caused by high frequency operation. Another way to address this problem is to simply limit the duration of the high frequency excursions, which duration may be limited to the duration for the various components that are affected by the high frequency operation to reach a design or threshold temperature. Other techniques to mitigate the increased heating include the providing of fans for convective cooling. However, the degree of convective cooling is dependent upon the surface area, air velocity, air properties, and the absolute temperature difference of the components from the ambient. Radiant transport has also been employed to cool devices, but the radiant transport is also dependent upon the device surface area, surface irradiative properties, and temperature difference from the environment.
All of the aforementioned approaches to accommodating the bursts of high frequency operation may incur undesirable consequences. For one, the use of oversized components to absorb heat adds to component and system cost, especially for power supplies and voltage regulators, and expends more energy at normal operating frequencies of a CPU, which leads to decreased battery life for mobile computing devices. Moreover, the use of fans to provide cooling is costly and consumes significant amounts of energy, thereby increasing material costs and decreasing battery life. High volumetric flow fans can also cause unacceptable noise to be generated and thereby place stringent demands on the mechanical, electronic and industrial designs of systems to accommodate such fans. In addition, radiant transport to provide component/system cooling is generally small (relative to the conductive and convective transport) at the typical operating temperatures required by electronic components.
Accordingly, there may be a need for improved techniques and apparatus to solve these and other problems.